.yxhw-ul{
    position:fixed;
    top:0.8rem;
    left:0;
    width:100vw;
    height:0.6rem;
    background-color: white;
    display: flex;
    justify-content: space-around;
    list-style-type: none;
    font-size: 0.3rem;
    margin-bottom: 0.5rem;
}
.yxhw-active{
    border-bottom: 1px solid red;
    color:red;
}
.yan{
    height:5rem;
    width:100vw;
    position:fixed;
    top:0;
    left:0;
    background-color: white;
}